A senior official of the power ministry told ET that the ministry had written to the coal ministry on December 30, 2011, saying the infrastructure for introducing the GCV system was not yet in place.

Following the migration to the new system, NTPC, the largest consumer of the state-owned monopoly Coal India and the biggest power producer in the country, is set to see its coal bill rise 40%, to Rs 28,000 crore a year from Rs 20,000 crore.

"We consume about one-third of the coal produced by Coal India and our preliminary estimates show that the price of C and D grade coal is expected to double following the introduction of the new system," an NTPC official who did not wish to be identified said.

The official said NTPC had also requested the power ministry to take up the issue with the coal ministry. Despite the request, Coal India moved to the new system from January 1, the official of the power ministry quoted earlier said.

"Nevertheless, the power ministry has now entered into talks with the coal ministry for keeping the migration at an abeyance. There is another meeting scheduled between all stakeholders next week," he said. GCV, which measures the amount of heat liberated by carbon and hydrogen in the coal when it is heated, is an internationally accepted pricing mechanism.